This invention relates to an oxygen generation device comprising a plurality of oxygen generation elements automatically sequentially decomposed one at a time so as not to interrupt the generation of oxygen, and more particularly to a control and monitoring system for such an oxygen generation device by which the user can confirm whether or not oxygen is being normally generated.
Chemical oxygen generation elements, including principally compounds generating oxygen through chemical reaction of thermal decomposition, are suitable for use with portable, small-sized oxygen generation devices, because the heavy, pressure-proof vessels are not required for the operation of such generation elements. These chemical oxygen generation elements are most typically chlorate system elements and are called chlorate candles. A chlorate candle is comprised principally of alkali metal chlorate and has subsidiary agents such as an exothermic agent and a chlorine absorbent and is shaped into a candle by being filled into a canister. Upon ignition of one end thereof by a detonator, electric heater, or the like, the chlorate candle starts to decompose so as to generate oxygen and also generates heat. It continues to decompose through a chain reaction owing to the self generated heat of decomposition, resulting in the continuous generation of oxygen. Such chemical oxygen generation elements, which can be readily manufactured, have a lifetime on the order of from 10 to 30 minutes. Thus when it is required to generate oxygen for a long period of time such as one hour or more, the stable generation of the oxygen is more easily achieved by preparing a plurality of small-sized chlorate candles and sequentially igniting them so as not to interrupt the generation of oxygen rather than provide a single large-sized candle. In this case however, when the oxygen generation element in the process of being decomposed has completed or nearly completed its generation of oxygen, the succeeding candle must be ignited immediately. Sequential ignition systems for this purpose are preferably simple to manipulate and reliable in operation because they are frequently employed for equipment used in an emergency.
If such sequential ignition systems get out of order, or if there is a failure of the ignitor, or a fall-off or suspension of the decomposition by reason of a malfunction of the oxygen generation elements, it is necessary to immediately signal the user so that he may take the required countermeasures, unless the suspension of oxygen generation is of a duration short enough to cause no hindrance to the use of the equipment in which the oxygen generation elements are provided. Further, devices for generating oxygen for long periods of time preferably include means for indicating during operation approximately how much capacity to generate oxygen remains.
Conventional oxygen generation devices comprising a plurality of oxygen generation elements have been provided with coutermeasures for the described problems only to a very limited extent, and such devices commonly require the utmost attention and complicated manipulations by the user.
Accordingly, it is an object of the present invention to provide a control and monitoring system for an oxygen generation device which does not require such close attention and such complicated manipulations by the user and which prevents failure due to the interruption of oxygen generation.